Filter and barrier

Abstract

An elongate barrier material comprising an elongate apertured load-bearing sheet material and an elongate apertured filter material attached to the load-bearing sheet material. The apertures in the filter material have an ASTM D-4751 size less than 500μ and the size of the apertures in the load-bearing material is at least 4 times the size of the apertures in the filter material. The length of the filter material can be changed elastically so that the barrier material can be transported in the form of a roll which can be unrolled for installation.

The invention claimed is: 
     
       1. A barrier material which comprises
 (i) an elongate load-bearing apertured sheet material and 
 (ii) an elongate apertured sheet filter material which is attached to the load-bearing apertured sheet material, 
 
       the load-bearing apertured sheet material comprising
 (A) a first set of melt-extruded polymeric strands which are (i) parallel to each other and (ii) spaced apart from each other with a distance between adjacent strands of 0.1 to 0.5 inch, and 
 (B) a second set of melt-extruded polymeric strands which are (i) parallel to each other, (ii) spaced apart from each other with a distance between adjacent strands of 0.1 to 0.5 inch, and (iii) at an angle to the first strands; 
 the first and second sets of polymeric strands (a) being bonded to each other at crossover sections at which the polymeric strands are bonded together, and (b) forming open apertures which have a first aperture size, measured by the procedure of ASTM D-4751, and 
 
       the filter material 
       (1) comprising
 (A) a first set of melt-extruded polymeric strands which are (i) parallel to each other and (ii) spaced apart from each other, and 
 (B) a second set of melt-extruded polymeric strands which are (i) parallel to each other, (ii) spaced apart from each other, and (iii) at an angle of 50-80° to the first strands; 
 the first and second sets of polymeric strands (a) being bonded to each other at crossover sections at which the polymeric strands are bonded together, and (b) forming open apertures which have a second aperture size, measured by the procedure of ASTM D-4751, the second aperture size being less than 500μ (0.500 mm) and the first aperture size being at least 4 times the second aperture size, 
 
       (2) having a percentage open area (measured by COE 02215-86) of at least 25%, and 
       (3) having a length which can be changed elastically by at least 0.03%. 
     
     
       2. A barrier material according to  claim 1  wherein (i) the second aperture size is less than 400μ and (ii) the first aperture size is at least 8 times the second aperture size. 
     
     
       3. A barrier material according to  claim 2  which consists essentially of (i) the load-bearing sheet material, (ii) the filter material and (iii) means securing the filter material to the load-bearing sheet material. 
     
     
       4. A barrier material according to  claim 2  which has a length of at least 25 feet and wherein the filter material has a thickness of less than 0.06 inch. 
     
     
       5. A barrier material according to  claim 4  wherein the length of the filter material can be changed elastically by at least 0.1%. 
     
     
       6. A barrier material according to  claim 5  which is in the form of multiple layers wrapped around a core having a diameter of 1-6 inch. 
     
     
       7. An area of ground which comprises a barrier material according to  claim 1  which has been installed along an extended barrier line on the ground. 
     
     
       8. A barrier material which comprises (i) an elongate load-bearing apertured sheet material and (ii) an elongate apertured sheet filter material which is attached to the load-bearing apertured sheet material,
 the load-bearing apertured sheet material 
 (1) comprising
 (A) a first set of melt-extruded polymeric strands which are (i) parallel to each other and (ii) spaced apart from each other with a distance between adjacent strands of 0.1 to 0.5 inch, and 
 (B) a second set of melt-extruded polymeric strands which are (i) parallel to each other, (ii) spaced apart from each other with a distance between adjacent strands of 0.1 to 0.5 inch, and (iii) at an angle of 60-80° to the first strands; 
 the first and second sets of polymeric strands (i) being bonded to each other at crossover sections at which the polymeric strands are bonded together, and (ii) forming open apertures which have a first aperture size, measured by the procedure of ASTM D-4751, and 
 
 (2) having a percentage open area (measured by COE 02215-86) of at least 35%; 
 and the filter material 
 (1) comprising
 (A) a first set of melt-extruded polymeric strands which are (i) parallel to each other and (ii) spaced apart from each other, and 
 (B) a second set of melt-extruded polymeric strands which are (i) parallel to each other, (ii) spaced apart from each other, and (iii) at an angle of 50-80° to the first strands; 
 the first and second sets of polymeric strands (i) being bonded to each other at crossover sections at which the polymeric strands are bonded together, and (ii) forming open apertures which have a second aperture size, measured by the procedure of ASTM D-4751, the second aperture size being less than 400μ and the first aperture size being at least 4 times the second aperture size, 
 
 (2) having a percentage open area (POA measured by COE 02215-86) of at least 30%, 
 (3) having a length which can be changed elastically by at least 0.1%, and 
 (4) has a thickness of 0.01-0.04 inch. 
 
     
     
       9. A barrier material according to  claim 8  wherein (i) the second aperture size is less than 400μ and (ii) the first aperture size is at least 8 times the second aperture size. 
     
     
       10. A barrier material according to  claim 9  wherein the second aperture size is 200-400μ. 
     
     
       11. A barrier material according to  claim 8  wherein the filter material has a percentage open area of about 55%. 
     
     
       12. A barrier material according to  claim 8  which has a length of at least 25 feet and wherein the filter material has a thickness of less than 0.06 inch. 
     
     
       13. A barrier material according to  claim 12  wherein the length of the filter material can be changed elastically by at least 0.1%. 
     
     
       14. A barrier material according to  claim 8  wherein the filter material has a thickness 0.015-0.03 inch and a width of at least 4 inch. 
     
     
       15. A barrier material according to  claim 8  which consists essentially of (i) the load-bearing sheet material, (ii) the filter material and (iii) means securing the filter material to the load-bearing sheet material. 
     
     
       16. A barrier material according to  claim 8  which is in the form of multiple layers wrapped around a core having a diameter of 1-6 inch. 
     
     
       17. An area of ground which comprises a barrier material according to  claim 8  which has been installed along an extended barrier line on the ground. 
     
     
       18. An elongate filter material which
 (1) comprises
 (A) a first set of melt-extruded polymeric strands which are (i) parallel to each other and (ii) spaced apart from each other, and 
 (B) a second set of melt-extruded polymeric strands which are (i) parallel to each other, (ii) spaced apart from each other, and (iii) at an angle of 50-80° to the first strands; 
 
 the first and second sets of polymeric strands (i) being bonded to each other at crossover sections at which the polymeric strands are bonded together, and (ii) forming open apertures which have an aperture size, measured by the procedure of ASTM D-4751, which is less than 500μ (0.500 mm), 
 (2) has a percentage open area (measured by COE 02215-86) of at least 25%, 
 (3) has a thickness of less than 0.060 inch, and 
 (4) has a length of at least 25 feet which can be changed elastically by at least 0.05%. 
 
     
     
       19. A filter material according to  claim 18  which has an aperture size of 200-300 μm and whose length can be changed elastically by at least 0.1%. 
     
     
       20. A filter material according to  claim 18  which has a thickness of 0.015-0.03 inch and a width of 6 to 36 inch.